Understanding confirmed predictions in quantum gravity
Feynmanâs relativistic path integral replaces the non-relativistic 1st quantization indeterminancy principle (required when using a classical Coulomb field in quantum mechanics) with a simple physical mechanism, multipath interference between small mechanical interactions. Each mechanical interaction is represented by a Feynman Moller scattering diagram (Fig. 1) for a gauge boson emitted by one charge to strike an effective interaction cross-section of the other charge, a cross-sectionl that is proportional to the square of the interaction strength or running coupling. Each additional pair of vertices in a Feynman diagram reduce its relative contribution to the path integral by a factor of the coupling, so for a force with a very small couplings like observable (low energy) quantum gravity, only the 2-vertex Feynman diagram has an appreciable contribution, allowing a very simple calculation to check the observable (low energy) quantum gravity interaction strength. Evidence is given that quantum gravity arises from a repulsive U(1) gauge symmetry which also causes the cosmological acceleration.